It’s not really a critique of someone gawping at a big number to then go and gawp at a bigger one. These two numbers are only related in that they express volumes of water.
The context for the comment was that lawns consume water on a scale comparable to all domestic agricultural irrigation, or half of all the domestic reticulated water supply, and it’s not doing much beyond aesthetics. That is significant use of a precious resource by any measure, and a wasteful one by most people’s. If the amount of water in Lake Superior or the Mississippi were relevant to the relatively small water consumption for domestic use and agriculture, why would anyone be bothered about droughts? Just send in the barges!
Whether lawns are environmentally ruinous by dint of sucking up that much drinking water is a different argument. New builds clearing woodlands in order to have more acreage and monoculture lawns displacing native species / food webs are problems, but there’s certainly worse things you could do with an existing yard.
> These two numbers are only related in that they express volumes of water.
No, these three numbers are related in that they express volumes of fresh water consumed per year for particular uses in the United States. The Mississippi River is dumping 16.8 megaliters per second of freshwater into the ocean. In that context, it's totally inconsequential if people in the US spray 0.2 megaliters per second of freshwater onto their lawns.
> That is significant use of a precious resource by any measure
No, it is not.
> aesthetics. ... a wasteful [use] by most people’s [measure].
Beautifying our surroundings is not a wasteful use of resources by most people's measure; if it were, the mandatory lawn ordinances people are (rightly) decrying in this thread wouldn't have been voted in. We have seen what the results look like when people consider aesthetics "wasteful": Pruitt-Igoe, prisons, concentration camps, Soviet housing blocks, American high schools, battleships, the Pentagon, the bulldozing of forests and mountains to build parking lots. Humans do not flourish in these environments.
Instead, let us aspire to consider things wasteful that cannot be aesthetically justified!
The broader cultural context is, I think, that this lamentation of other people watering their lawns stems from the same misguided Judeo-Christian asceticism that led medieval hermits to never bathe and wear hairshirts, equating happiness, enjoyment, and comfort with sin, self-indulgence, and dissolution. Sometimes you see people from Judeo-Christian traditions attempting to justify such concepts by appropriating Buddhism, apparently unaware of the profound attention to aesthetics easily observable in any Buddhist temple or monastery.
This ascetisism has been twisted into a simplistic zero-sum pseudo-environmentalism—sometimes coupled with a feigned charity toward the poor—that equates material wealth with environmental destruction and impoverishment of others, and so seeks to ameliorate California's periodic droughts with showerhead flow restrictors and more restrictive central lawn planning.
> If the amount of water in Lake Superior or the Mississippi were relevant to the relatively small water consumption for domestic use and agriculture, why would anyone be bothered about droughts?
Probably because you're not building enough canals and pipelines to transport freshwater from the Mississippi (and other rivers) to US agricultural lands. Get on it! A lot of those rivers are already full of fertilizer! Also, it's a problem when half of California catches on fire, even if nobody's almonds burn.
The context for the comment was that lawns consume water on a scale comparable to all domestic agricultural irrigation, or half of all the domestic reticulated water supply, and it’s not doing much beyond aesthetics. That is significant use of a precious resource by any measure, and a wasteful one by most people’s. If the amount of water in Lake Superior or the Mississippi were relevant to the relatively small water consumption for domestic use and agriculture, why would anyone be bothered about droughts? Just send in the barges!
Whether lawns are environmentally ruinous by dint of sucking up that much drinking water is a different argument. New builds clearing woodlands in order to have more acreage and monoculture lawns displacing native species / food webs are problems, but there’s certainly worse things you could do with an existing yard.